U.S. patent application number 12/289541 was filed with the patent office on 2009-05-21 for dye-sensitized solar cell.
This patent application is currently assigned to Aurotek Corporation. Invention is credited to Chung-Hua Li, Hung-Chieh Tsai.
Application Number | 20090126789 12/289541 |
Document ID | / |
Family ID | 40640674 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090126789 |
Kind Code |
A1 |
Li; Chung-Hua ; et
al. |
May 21, 2009 |
Dye-sensitized solar cell
Abstract
The present invention relates to a dye-sensitized solar cell
that exhibits improved photoabsorption efficiency and
optoelectronic conversion efficiency in the long-wavelength region.
The dye-sensitized solar cell of the present invention, in
coordination with an outer loop, comprises: a first substrate; a
second substrate; and a photoenergy conversion layer disposed
between the first substrate and the second substrate. Herein, the
photoenergy conversion layer comprises an electrolytic condensed
matter and pluralities of dye-adsorbed units dispersed in the
electrolytic condensed matter. In addition, a first photonic
crystal layer is disposed on the surface of the first substrate. A
beam of light from the external environment can pass through the
first photonic crystal layer and the first substrate to arrive in
the photoenergy conversion layer. The photoenergy conversion layer
can convert the photoenergy of the light to electric energy and the
outer loop electrically connects to the first substrate and the
second substrate.
Inventors: |
Li; Chung-Hua; (Taipei City,
TW) ; Tsai; Hung-Chieh; (Tainan City, TW) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE, FOURTH FLOOR
ALEXANDRIA
VA
22314-1176
US
|
Assignee: |
Aurotek Corporation
Taipei
TW
|
Family ID: |
40640674 |
Appl. No.: |
12/289541 |
Filed: |
October 30, 2008 |
Current U.S.
Class: |
136/256 |
Current CPC
Class: |
Y02E 10/542 20130101;
H01G 9/2059 20130101; H01G 9/209 20130101; H01G 9/2031 20130101;
H01G 9/2068 20130101 |
Class at
Publication: |
136/256 |
International
Class: |
H01L 31/00 20060101
H01L031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 30, 2007 |
TW |
096140766 |
Claims
1. A dye-sensitized solar cell, in coordination with an outer loop,
comprising: a first substrate; a second substrate; and a
photoenergy conversion layer, disposed between the first substrate
and the second substrate and comprising an electrolytic condensed
matter and pluralities of dye-adsorbed units dispersed in the
electrolytic condensed matter; wherein, a first photonic crystal
layer is disposed on the surface of the first substrate, a beam of
light from the external environment passes through the first
photonic crystal layer and the first substrate to arrive in the
photoenergy conversion layer, the photoenergy conversion layer
converts photoenergy of the light to electric energy, and the outer
loop electrically connects to the first substrate and the second
substrate.
2. The dye-sensitized solar cell as claimed in claim 1, further
comprising a first transparent conductor disposed on one side of
the first substrate adjacent to the photoenergy conversion layer,
wherein the first transparent conductor and the first photonic
crystal layer are disposed on the two sides of the first substrate,
and the first transparent conductor electrically connects to the
outer loop.
3. The dye-sensitized solar cell as claimed in claim 1, wherein the
first substrate is disposed between the first photonic crystal
layer and the photoenergy conversion layer.
4. The dye-sensitized solar cell as claimed in claim 1, further
comprising a second transparent conductor disposed on one side of
the second substrate adjacent to the photoenergy conversion layer,
and the second transparent conductor electrically connects to the
outer loop.
5. The dye-sensitized solar cell as claimed in claim 1, further
comprising a second photonic crystal layer disposed on the surface
of the second substrate.
6. The dye-sensitized solar cell as claimed in claim 5, wherein the
second photonic crystal layer is disposed on the surface of the
second substrate adjacent to the photoenergy conversion layer.
7. The dye-sensitized solar cell as claimed in claim 5, further
comprising a second transparent conductor disposed between the
second photonic crystal layer and the photoenergy conversion layer
and electrically connecting to the outer loop.
8. The dye-sensitized solar cell as claimed in claim 1, wherein the
first photonic crystal layer is formed on the surface of the first
substrate by an etching process for definition of a nanocapsule
array.
9. The dye-sensitized solar cell as claimed in claim 8, wherein the
etching process for definition of a nanocapsule array uses
nanocapsules made of silicon oxide.
10. The dye-sensitized solar cell as claimed in claim 1, wherein
the first photonic crystal layer comprises pluralities of spherical
hollow portions.
11. The dye-sensitized solar cell as claimed in claim 10, wherein
the spherical hollow portions are in the shape of a sphere.
12. The dye-sensitized solar cell as claimed in claim 1, wherein
the first photonic crystal layer comprises pluralities of
photoresist units.
13. The dye-sensitized solar cell as claimed in claim 1, wherein
the first photonic crystal layer functions as an anti-reflective
layer.
14. The dye-sensitized solar cell as claimed in claim 5, wherein
the second photonic crystal layer comprises at least one
nanocapsule layer, and the nanocapsule layer comprises pluralities
of nanocapsules.
15. The dye-sensitized solar cell as claimed in claim 14, wherein
the nanocapsules are made of silicon oxide.
16. The dye-sensitized solar cell as claimed in claim 5, wherein
the second photonic crystal layer is a distributed Bragg
reflector.
17. The dye-sensitized solar cell as claimed in claim 5, wherein
the second photonic crystal layer is a reflective layer.
18. The dye-sensitized solar cell as claimed in claim 1, wherein
the first substrate and the second substrate are made of
polyethylene terephthalate.
19. The dye-sensitized solar cell as claimed in claim 1, wherein
the first substrate and the second substrate are made of glass.
20. The dye-sensitized solar cell as claimed in claim 2, wherein
the first transparent conductor is made of indium tin oxide.
21. The dye-sensitized solar cell as claimed in claim 4, wherein
the second transparent conductor is made of indium tin oxide.
22. The dye-sensitized solar cell as claimed in claim 7, wherein
the second transparent conductor is made of indium tin oxide
23. The dye-sensitized solar cell as claimed in claim 1, wherein
the electrolytic condensed matter comprises pluralities of redox
mediators.
24. The dye-sensitized solar cell as claimed in claim 1, wherein
the dye-adsorbed units comprise pluralities of titanium oxide
nanocapsules.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a dye-sensitized solar cell
and, more particularly, to a dye-sensitized solar cell that
exhibits improved photoabsorption efficiency and optoelectronic
conversion efficiency in the long-wavelength region.
[0003] 2. Description of Related Art
[0004] Since the various finite energy sources (such as uranium,
natural gas, petroleum and so on) on which people rely will be
exhausted before long, large amounts of money and effort are being
spent to develop the application of alternative energy (i.e. "green
energy"), such as solar energy, wind power, wave power and
terrestrial heat. However, among the above-mentioned various kinds
of green energy, the applications of wind power, wave power and
terrestrial heat are restricted to specific areas, such as volcano
areas or seaboards. In addition, the equipment for the employment
of the aforementioned energy is in large-scale, such as windmills,
deep seawater intake pipes, and so on, resulting in the restriction
on the application of the green energy.
[0005] On the contrary, solar energy can be applied in any area
that can be illuminated by sunshine. Thereby, the solar energy
industry is viewed as a most favorable industry, and thereby great
amounts of resources are committed to develop solar cells and the
related devices. However, the development of silicon solar cells
faces a bottleneck, due to the insufficient production and high
cost of silicon that is the main material used in a solar cell, the
high cost of machinery for manufacturing solar cells, low speed of
mass production for solar cells, and the difficulty in improving
optoelectronic conversion efficiency of solar cells.
[0006] In view of the above-mentioned situation, another type of
solar cell, dye-sensitized solar cells (DSSC), has been developed
to enhance the absorption of visible-light through dyestuffs
attached on the wide band-gap semiconductor materials so as to
convert photoenergy into electric energy.
[0007] A conventional dye-sensitized solar cell is illustrated in
FIG. 1, comprising: a first substrate 11, a second substrate 12 and
a photoenergy conversion layer 13 disposed between the first
substrate 11 and the second substrate 12. Herein, the photoenergy
conversion layer 13 comprises an electrolytic condensed matter 131
and pluralities of dye-adsorbed units 132, and the dye-adsorbed
units 132 are dispersed in the electrolytic condensed matter 131.
In addition, the conventional solar cell is operated in
coordination with an outer loop 10, and the first substrate 11 and
the second substrate 12 electrically connect to the outer loop 10.
Furthermore, the electrolytic condensed matter 131 of the
photoenergy conversion layer 13 comprises pluralities of redox
mediators, and the dye-adsorbed units 132 comprise pluralities of
titanium oxide nanocapsules. In the conventional dye-sensitized
solar cell, a first transparent conductor 14 is disposed on a side
of the first substrate 11 adjacent to the photoenergy conversion
layer 13, and the first transparent conductor 14 electrically
connects to the aforementioned outer loop 10. The second
transparent conductor 15 is disposed on a side of the second
substrate 12 adjacent to the photoenergy conversion layer 13, and
the second transparent conductor 15 electrically connects to the
aforementioned outer loop 10.
[0008] During the operation of the conventional dye-sensitized
solar cell, a beam of light from the external environment passes
through the first substrate 11 and the first transparent conductor
14, and arrives in the photoenergy conversion layer 13. However,
the light may pass through the second transparent conductor 15 and
the second substrate 12 to leave the conventional dye-sensitized
solar cell. Alternatively, the light is reflected from the
dye-adsorbed units 132, and then passes through the first
transparent conductor 14 and the first substrate 11 to leave the
conventional dye-sensitized solar cell. Thereby, the conventional
dye-sensitized solar cell cannot thoroughly convert photoenergy
into electric energy, so that the optoelectronic conversion
efficiency of the conventional dye-sensitized solar cell cannot be
further enhanced.
[0009] In addition, with reference to FIG. 2, there is shown a
photoabsorption efficiency-wavelength diagram of each component in
the conventional dye-sensitized solar cell. The curve A represents
the correlation between photoabsorption efficiency of the titanium
oxide nanocapsules in the photoenergy conversion layer and
wavelength. The curve B represents the correlation between
photoabsorption efficiency of the first dyestuff RuL.sub.3 in the
photoenergy conversion layer and wavelength. The curve C represents
the correlation between photoabsorption efficiency of the second
dyestuff RuL'(NCS).sub.3 in the photoenergy conversion layer and
wavelength.
[0010] As shown in FIG. 2, the absorption of the titanium oxide
nanocapsules in the photoenergy conversion layer is maximized at
the wavelength less than 400 nm (curve A); and the absorption of
the first dyestuff RuL.sub.3 and the second dyestuff
RuL'(NCS).sub.3 in the photoenergy conversion layer is maximized in
the range of from 400 nm to 800 nm (curves B and C). That is, the
light with the wavelength larger than 800 nm cannot be efficiently
absorbed by the conventional dye-sensitized solar cell and thus
cannot be converted into electric energy. Thereby, in the
long-wavelength region (larger than 800 nm), the optoelectronic
conversion efficiency of the conventional dye-sensitized solar cell
cannot be efficiently enhanced.
[0011] Accordingly, there is an unfulfilled need for a
dye-sensitized solar cell with improved absorption efficiency and
optoelectronic conversion efficiency in the long-wavelength
range.
SUMMARY OF THE INVENTION
[0012] The object of the present invention is to provide a
dye-sensitized solar cell that exhibits improved photoabsorption
efficiency in the long wavelength range.
[0013] Another object of the present invention is to provide a
dye-sensitized solar cell that has improved optoelectronic
conversion efficiency.
[0014] To achieve the object, the dye-sensitized solar cell of the
present invention, in coordination with an outer loop, comprises: a
first substrate, a second substrate, and a photoenergy conversion
layer disposed between the first substrate and the second
substrate. Herein, the photoenergy conversion layer comprises an
electrolytic condensed matter and pluralities of dye-adsorbed
units, and the dye-adsorbed units are dispersed in the electrolytic
condensed matter. In the present invention, a first photonic
crystal layer is disposed on the surface of the first substrate. A
beam of light from the external environment can pass through the
first photonic crystal layer and the first substrate to arrive in
the photoenergy conversion layer. The photoenergy conversion layer
can convert the photoenergy of the light to electric energy. The
outer loop electrically connects to the first substrate and the
second substrate.
[0015] Accordingly, the dye-sensitized solar cell of the present
embodiment can convert the photoenergy of the long-wavelengthed
light to electric energy by the photonic crystal layers (such as
the first and second photonic crystal layers) disposed therein.
That is, the dye-sensitized solar cell of the present embodiment
can efficiently employ the photoenergy of light that cannot be
employed in a conventional dye-sensitized solar cell, such as an
infrared ray. Thereby, in the long-wavelength range, the
dye-sensitized solar cell of the present embodiment has improved
absorption efficiency and optoelectronic conversion efficiency so
as to replace a current silicon solar cell and be a future most
favored technology in the green energy industries.
[0016] In the dye-sensitized solar cell of the present invention,
the first photonic crystal layer can be formed on the surface of
the first substrate by any method. Preferably, the first photonic
crystal layer is formed on the surface of the first substrate by an
etching process for definition of a nanocapsule array, a process
for stacking one or pluralities of nanocapsule layers on the
surface of the first substrate, a nano-imprinting process, or a
photography process. Herein, the nanocapsules used in the
aforementioned etching process for definition of a nanocapsule
array can be made of any material. Preferably, the nanocapsules are
made of silicon oxide, polymethyl methacrylate or polystyrene. In
addition, the first photonic crystal layer of the present invention
can be in any type. Preferably, the first photonic crystal layer
consists of one nanocapsule layer, pluralities of nanocapsule
layers, pluralities of photoresist units, or pluralities of
spherical hollow portions. The pluralities of nanocapsules in the
nanocapsule layer(s) can be made of any material. Preferably, the
material of the nanocapsules is silicon oxide, silicon, polymethyl
methacrylate, polystyrene, or titanium oxide. The pluralities of
photoresist units can be in any structure. Preferably, the
photoresist units are in the shape of a cylinder, an elliptic
cylinder, or an oblong pillar. The pluralities of spherical hollow
portions can be in any shape. Preferably, the spherical hollow
portions are in the shape of a sphere or an ellipse.
[0017] In the dye-sensitized solar cell of the present invention,
the second photonic crystal layer can be formed on the surface of
the second substrate by any method. Preferably, the second photonic
crystal layer is formed on the surface of the second substrate by
an etching process for definition of a nanocapsule array, a process
for stacking one or pluralities of nanocapsule layers on the
surface of the second substrate, a nano-imprinting process, or a
photography process. In addition, the second photonic crystal layer
of the present invention can be in any type. Preferably, the second
photonic crystal layer is a distributed Bragg reflector or consists
of one nanocapsule layer or pluralities of nanocapsule layers. The
pluralities of nanocapsules in the nanocapsule layer(s) can be made
of any material. Preferably, the material of the nanocapsules is
silicon oxide, silicon, polymethyl methacrylate, polystyrene, or
titanium oxide.
[0018] In the dye-sensitized solar cell of the present invention,
the first substrate can be made of any material. Preferably, the
first substrate is made of glass, polyethylene terephthalate,
polyethylene naphthalate, polyethyl sulfone or polycarbonate. In
the dye-sensitized solar cell of the present invention, the second
substrate can be made of any material. Preferably, the second
substrate is made of glass, polyethylene terephthalate,
polyethylene naphthalate, polyethyl sulfone or polycarbonate. In
the dye-sensitized solar cell of the present invention, the first
transparent conductor can be made of any material. Preferably, the
first transparent conductor is made of indium tin oxide, indium
zinc oxide, zinc aluminum oxide, or zinc gallium oxide. In the
dye-sensitized solar cell of the present invention, the second
transparent conductor can be made of any material. Preferably, the
second transparent conductor is made of indium tin oxide, indium
zinc oxide, zinc aluminum oxide, or zinc gallium oxide.
[0019] Other objects, advantages, and novel features of the
invention will become more apparent from the following detailed
description when taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a perspective view of a conventional
dye-sensitized solar cell;
[0021] FIG. 2 is a photoabsorption efficiency-wavelength diagram of
each component in a conventional dye-sensitized solar cell;
[0022] FIG. 3 is a perspective view of a dye-sensitized solar cell
in a first preferred embodiment of the present invention;
[0023] FIG. 4 is a perspective view of an etching process for
definition a nanocapsule array to form a first photonic crystal
layer on the surface of a first substrate of a first preferred
embodiment of the present invention;
[0024] FIGS. 5A to 5B are a perspective view of a process for
stacking nanocapsules to form a second photonic crystal layer on
the surface of a second substrate of a first preferred embodiment
of the present invention;
[0025] FIG. 6 is a photoabsorption efficiency-wavelength diagram of
each component in a dye-sensitized solar cell of a first preferred
embodiment;
[0026] FIG. 7 is a perspective view of a dye-sensitized solar cell
in a second preferred embodiment of the present invention; and
[0027] FIG. 8 is a perspective view of a dye-sensitized solar cell
in a third preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] As shown in FIG. 3, there is shown a perspective view of a
dye-sensitized solar cell in a first embodiment of the present
invention, comprising: a first substrate 31, a second substrate 32,
and a photoenergy conversion layer 33 disposed between the first
substrate 31 and the second substrate 32. Herein, the photoenergy
conversion layer 33 comprises an electrolytic condensed matter 331
and pluralities of dye-adsorbed units 332, and the dye-adsorbed
units 332 are dispersed in the electrolytic condensed matter 331.
In the first embodiment, the electrolytic condensed matter 331 of
the photoenergy conversion layer 33 comprises pluralities of redox
mediators, and the dye-adsorbed units 332 comprise pluralities of
titanium oxide nanocapsules.
[0029] In addition, the dye-sensitized solar cell of the first
embodiment is operated in coordination with an outer loop 30, and
the first substrate 31 and the second substrate 32 electrically
connect to the outer loop 30. Furthermore, in the dye-sensitized
solar cell of the first embodiment, a first photonic crystal layer
34 is disposed on the surface 311 of the first substrate 31, and a
second photonic crystal layer 35 is disposed on the surface 321 of
the second substrate 32. Moreover, a first transparent conductor 36
is disposed on a side of the first substrate 31 adjacent to the
photoenergy conversion layer 33, so that the first transparent
conductor 36 and the first photonic crystal layer 34 are disposed
on the two sides of the first substrate 31, respectively. The first
transparent conductor 36 electrically connects to the
aforementioned outer loop 30. The second transparent conductor 37
is disposed between the second photonic crystal layer 35 and the
photoenergy conversion layer 33 and electrically connects to the
aforementioned outer loop 30.
[0030] During the operation of the dye-sensitized solar cell of the
first embodiment, a beam of light from the external environment
passes through the first photonic crystal layer 34, the first
substrate 31 and the first transparent conductor 36 in sequence to
arrive in the photoenergy conversion layer 33. In the first
embodiment, the first photonic crystal layer 34 can function as an
anti-reflective layer and a dispersion layer, and thereby the
aforementioned light can efficiently pass through the first
photonic crystal layer 34. Besides, the photonic crystal structure
has the effect of photo confinement and the second photonic crystal
layer 35 can function as a reflective layer, so that the
aforementioned light arriving in the photoenergy conversion layer
33 can be reflected from the second photonic crystal layer 35 and
pass through the photoenergy conversion layer 33 many times. That
is, the light is confined to the photoenergy conversion layer 33.
Thereby, the photoenergy conversion layer 33 can thoroughly convert
the photoenergy of the light that is confined to the photoenergy
conversion layer 33 of the dye-sensitized solar cell of the first
embodiment to electric energy. Accordingly, in comparison to a
conventional dye-sensitized solar cell, the dye-sensitized solar
cell of the present embodiment has higher optoelectronic conversion
efficiency. The conversion mechanism from photoenergy to electric
energy in the photoenergy conversion layer 33 is well known and
thereby is not mentioned here.
[0031] In the dye-sensitized solar cell of the first embodiment,
the structural sizes of the first and second photonic crystal
layers can be modified by the selection of diameter size of the
nanocapsules, and thereby the wavelength range of the light
available for the first and second photonic crystal layers can be
tuned. That is, in the dye-sensitized solar cell of the present
embodiment, by the suitable selection of structural sizes of the
first and second photonic crystal layers, the long-wavelengthed
light can successfully arrive in the photoenergy conversion layer
and is confined therein until the photoenergy of the light is
thoroughly converted to electric energy.
[0032] As shown in FIG. 3, in the dye-sensitized solar cell of the
first embodiment, the first substrate 31 and the second substrate
32 are made of glass, and the first transparent conductor 36 and
the second transparent conductor 37 are made of indium tin oxide
(ITO). In addition, the first photonic crystal layer 34 is formed
on the surface 311 of the first substrate 31 by an etching process
for definition of a nanocapsule array. The first photonic crystal
layer 34 is a two-dimensional photonic crystal including
pluralities of spherical hollow portions 341. The spherical hollow
portions 341 are in the shape of a sphere. The material of the
nanocapsules used in the above-mentioned etching process for
definition of a nanocapsule array is polymethyl methacrylate
(PMMA), and the detail steps of the etching process for definition
of a nanocapsule array are detailed as follows.
[0033] With reference to FIG. 4, a nanocapsule layer 41 including
pluralities of nanocapsules is first formed on the surface 311 of
the first substrate 31. The nanocapsules are made of polymethyl
methacrylate (PMMA) and have an average diameter in the range of
from 400 nm to 2000 nm. Subsequently, a silicon oxide (SiOx) layer
42 is formed on the partial surface of the first substrate 31 and
in the gaps within the nanocapsule layer 41 by vapor deposition,
and the first substrate 31 with the silicon oxide layer 42 thereon
undergoes an annealing process at a temperature in the range of
from 500.degree. C. to 900.degree. C.
[0034] After the completion of the annealing process, the first
substrate 31 with the silicon oxide layer 42 thereon is soaked in
formic acid (not shown in FIG. 4) to remove the aforementioned
nanocapsules. Accordingly, a two-dimensional photonic crystal (i.e.
the first photonic crystal layer 34) including pluralities of
spherical hollow portions 341 is formed on the surface 311 of the
first substrate 31. The suitable solution for removing the
nanocapsules depends on the material of the nanocapsules. That is,
the suitable solution for removing the nanocapsules made of silicon
oxide is HF solution; and the suitable solution for removing the
nanocapsules made of polystyrene is butanone or toluene.
[0035] As shown in FIG. 3, the second photonic crystal layer 35
includes pluralities of nanocapsule layers 351, and each of the
nanocapsule layers 351 includes pluralities of nanocapsules. That
is, the second photonic crystal layer 35 is formed by stacking
pluralities of nanocapsules on the surface 321 of the second
substrate 32, and the nanocapsules are made of silicon oxide. The
process for stacking the nanocapsules on the surface 321 of the
second substrate 32 is detailed as follows.
[0036] With reference to FIGS. 5A and 5B, a second substrate 32 and
a colloidal solution 51 are first provided. The colloidal solution
51 includes pluralities of nanocapsules and a surfactant.
Subsequently, the second substrate 32 is located in the container
52 filled with the colloidal solution 51 and soaked in the
colloidal solution 51. After placed for several minutes,
pluralities of nanocapsules gradually stack on the surface of the
second substrate 32 to form pluralities of nanocapsule layers 351.
Herein, the nanocapsules are made of silicon oxide and have an
average diameter in the range of from 150 nm to 450 nm. However,
the aforementioned process also can use polymethyl methacrylate,
polystyrene, or titanium oxide as the material of the nanocapsules,
and the size of the nanocapsules is not limited to the
above-mentioned range. Then, the volatile acetone 53 is poured in
the container 52 to evaporate the colloidal solution 51. After the
colloidal solution 51 has evaporated, the second substrate 32 is
taken out of the container 52 to obtain a second substrate 32 with
pluralities of nanocapsule layers 351 thereon.
[0037] With reference to FIG. 6, there is shown a photoabsorption
efficiency-wavelength diagram of each component in the
dye-sensitized solar cell of the first embodiment. The curve D
represents the correlation between photoabsorption efficiency of
the titanium oxide nanocapsules in the photoenergy conversion layer
and wavelength. The curve E represents the correlation between
photoabsorption efficiency of the first dyestuff RuL.sub.3 in the
photoenergy conversion layer and wavelength. The curve F represents
the correlation between photoabsorption efficiency of the second
dyestuff RuL'(NCS).sub.3 in the photoenergy conversion layer and
wavelength. The curve G represents the correlation between
photoabsorption efficiency of the dye-sensitized solar cell
including the first and second photonic crystal layers and
wavelength.
[0038] As shown in FIG. 6, the dye-sensitized solar cell of the
first embodiment can convert the photoenergy of the
long-wavelengthed light (with wavelength larger than 800 nm), such
as an infrared ray, to electric energy by the photonic crystal
layers (such as the first and second photonic crystal layers)
disposed therein. That is, the dye-sensitized solar cell of the
first embodiment can absorb and employ the photoenergy of infrared
ray that cannot be employed in a conventional dye-sensitized solar
cell. Thereby, in the long-wavelength range, the dye-sensitized
solar cell of the first embodiment has improved absorption
efficiency and optoelectronic conversion efficiency in comparison
to a conventional dye-sensitized solar cell.
[0039] FIG. 7 shows a perspective view of a dye-sensitized solar
cell in a second embodiment of the present invention, comprising: a
first substrate 71, a second substrate 72, and a
photoenergy-conversion layer 73 disposed between the first
substrate 71 and the second substrate 72. Herein, the photoenergy
conversion layer 73 comprises an electrolytic condensed matter 731
and pluralities of dye-adsorbed units 732, and the dye-adsorbed
units 732 are dispersed in the electrolytic condensed matter 731.
In addition, the dye-sensitized solar cell of the second embodiment
is operated in coordination with an outer loop 70, and the first
substrate 71 and the second substrate 72 electrically connect to
the outer loop 70. Furthermore, in the dye-sensitized solar cell of
the second embodiment, a first photonic crystal layer 74 is
disposed on the surface of the first substrate 71, and a second
photonic crystal layer 75 is disposed on the surface 721 of the
second substrate 72. Moreover, a first transparent conductor 76 is
disposed on a side of the first substrate 71 adjacent to the
photoenergy conversion layer 73, so that the first transparent
conductor 76 and the first photonic crystal layer 74 are disposed
on the two sides of the first substrate 71, respectively. The first
transparent conductor 76 electrically connects to the
aforementioned outer loop 70. The second transparent conductor 77
is disposed between the second photonic crystal layer 75 and the
photoenergy conversion layer 73 and electrically connects to the
aforementioned outer loop 70.
[0040] As shown in FIG. 7, in the dye-sensitized solar cell of the
second embodiment, the first substrate 71 and the second substrate
72 are made of polyethylene terephthalate, and the first
transparent conductor 76 and the second transparent conductor 77
are made of indium tin oxide (ITO). In addition, the first photonic
crystal layer 74 is formed on the surface of the first substrate 71
by a nano-imprinting process. The first photonic crystal layer 74
is a two-dimensional photonic crystal including pluralities of
spherical hollow portions 741. The spherical hollow portions 741
are in the shape of a sphere and integrated with the first
substrate 71. The second photonic crystal layer 75 functions as a
distributed Bragg reflector.
[0041] During the operation of the dye-sensitized solar cell of the
second embodiment, a beam of light from the external environment
passes through the first photonic crystal layer 74, the first
substrate 71 and the first transparent conductor 76 in sequence to
arrive in the photoenergy conversion layer 73 and is reflected from
the second photonic crystal layer 75 to pass through the
photoenergy conversion layer 73 many times and be confined therein.
Accordingly, in comparison to a conventional dye-sensitized solar
cell, the dye-sensitized solar cell of the second embodiment has
higher optoelectronic conversion efficiency.
[0042] FIG. 8 shows a perspective view of a dye-sensitized solar
cell in a third embodiment of the present invention, comprising: a
first substrate 81, a second substrate 82, and a photoenergy
conversion layer 83 disposed between the first substrate 81 and the
second substrate 82. Herein, the photoenergy conversion layer 83
comprises an electrolytic condensed matter 831 and pluralities of
dye-adsorbed units 832, and the dye-adsorbed units 832 are
dispersed in the electrolytic condensed matter 831. In addition,
the dye-sensitized solar cell of the third embodiment is operated
in coordination with an outer loop 80, and the first substrate 81
and the second substrate 82 electrically connect to the outer loop
80. Furthermore, in the dye-sensitized solar cell of the third
embodiment, a first photonic crystal layer 84 is disposed on the
surface 811 of the first substrate 81, and a second photonic
crystal layer 85 is disposed on the surface 821 of the second
substrate 82. Moreover, a first transparent conductor 86 is
disposed on a side of the first substrate 81 adjacent to the
photoenergy conversion layer 83, so that the first transparent
conductor 86 and the first photonic crystal layer 84 are disposed
on the two sides of the first substrate 81, respectively. The first
transparent conductor 86 electrically connects to the
aforementioned outer loop 80. The second transparent conductor 87
is disposed between the second photonic crystal layer 85 and the
photoenergy conversion layer 83 and electrically connects to the
aforementioned outer loop 80.
[0043] As shown in FIG. 8, in the dye-sensitized solar cell of the
third embodiment, the first substrate 81 and the second substrate
82 are made of glass, and the first transparent conductor 86 and
the second transparent conductor 87 are made of indium tin oxide
(ITO). In addition, the first photonic crystal layer 84 is formed
on the surface 811 of the first substrate 81 by a photographic
process to be a two-dimensional photonic crystal consisting of
plural photoresist units 841. The second photonic crystal layer 85
comprises a nanocapsule layer 851 including pluralities of
nanocapsules, and the nanocapsules are made of silicon oxide.
[0044] During the operation of the dye-sensitized solar cell of the
third embodiment, a beam of light from the external environment
passes through the first photonic crystal layer 84, the first
substrate 81 and the first transparent conductor 86 in sequence to
arrive in the photoenergy conversion layer 83 and is reflected from
the second photonic crystal layer 85 to pass through the
photoenergy conversion layer 83 many times and be confined therein.
Accordingly, in comparison to a conventional dye-sensitized solar
cell, the dye-sensitized solar cell of the third embodiment has
higher optoelectronic conversion efficiency.
[0045] All in all, the dye-sensitized solar cell of the present
invention can convert the photoenergy of the long-wavelengthed
light to electric energy by the photonic crystal layers (such as
the first and second photonic crystal layers) disposed therein.
That is, the dye-sensitized solar cell of the present invention can
efficiently employ the light that cannot be employed in a
conventional dye-sensitized solar cell, such as an infrared ray.
Thereby, in the long-wavelength range, the dye-sensitized solar
cell of the present invention has improved absorption efficiency
and optoelectronic conversion efficiency so as to replace a current
silicon solar cell and be a most favored technique in the green
energy industries.
[0046] Although the present invention has been explained in
relation to its preferred embodiment, it is to be understood that
many other possible modifications and variations can be made
without departing from the scope of the invention as hereinafter
claimed.
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